In recent years, an organic light emitting diode (OLED) display has gradually been paid more and more attention as a new type of flat panel display. Since it has characteristics of active luminescence, high luminous intensity, high resolution, wide visual angle, rapid response speed, low energy consumption and flexibility, the OLED display possibly becomes the Next-Generation display and replaces a liquid crystal display. For an OLED device, both an organic layer material and a metal electrode material therein are extremely sensitive to the moisture and oxygen, as a result if the OLED device is badly sealed, its product life will be greatly shortened. So the moisture and the oxygen are of a relative low content acceptable for the OLED device, which are 10−6 g/day/m2 and 10−3 cm3/day/m2, respectively. To meet such requirement, technologies for sealing the OLED device have been developed rapidly, which includes: film sealing, frit sealing, ultraviolet (UV) glue sealing, and dam and fill sealing.
In the related art, as compared with other sealing methods, the fit sealing method has been widely applied to seal medium and small size OLED devices, due to its significant advantages. By means of the frit sealing method, the frit is melted by heating with a movable laser beam in a nitrogen atmosphere, then the molten frit forms a hermetic sealing connection between upper glass substrate and lower glass substrate, thereby to provide a hermetic seal. Most currently used frit includes inorganic oxide sealing glass being as a basic material. The basic material is improved in dispersity by adding a dispersant, a filler, an organic solvent or the like; and it is improved in absorption to light by adding with elements such as Cu, Fe.
The existing fit sealing method has the following disadvantage: as the frit is of limited absorption to light, a laser having relative high power is desired. The risk of occurrence of a crack in the glass substrate will greatly increase when the laser having relative high power is used to irradiate.